Battery life is an important consideration in the design of wireless communication devices. Today, various power management techniques have been employed by manufacturers to reduce the average power consumption of the device, and thereby extend battery life. By way of example, efficient power management systems have emerged for second-generation (2G) voice communications in wireless communication devices equipped with code division multiple access (CDMA) technology. 2G CDMA systems are based on the TIA/EIA IS-95 CDMA standard, including IS-95A and IS-95B revisions. These standards are well known in the art. Today, it is not uncommon to find such devices with standby times of weeks and talk times of several hours. This is often achieved by intelligently switching the power to various processing resources.
To meet the growing demand for wireless services and high-speed data services, the third-generation (3G) of mobile services has recently emerged in the telecommunications industry. Much like the previous generation, CDMA provides the platform on which 3G services are provided. The International Telecommunication Union (ITU), working with industry bodies from around the world, defines and approves technical requirements and standards under the IMT-2000 (International Telecommunication Union-20 program).
Wireless communication devices with 3G services are feature rich multi-mode devices capable of supporting voice, high-speed Internet and multimedia communications. Some of the popular features on a high-end device, such as a mobile station modem (MSM) include: a MP3 player, a MPEG-4 decoder, Bluetooth, gpsOne, audio decoders, JPEG encoder/decoder, and the like. In many of these devices, the voice services are enhanced with live video. Some of these features may prohibit a power management scheme that interrupts the power source as is often done in devices supporting 2G services. This may result in a dramatic increase in average power consumption with the largest increases feeding the baseband circuitry, the memories and the display. Moreover consumer behavior studies indicate an increasing interest in lengthy connection of various digital services such as cameras and the Internet in the near future.
Various techniques have been proposed to reduce power consumption by wireless communication devices supporting 3G services. Some of the more common approaches include shrinking the device technology, caching, optimizing the front end architecture, using direct conversion transceivers, using foot and head switches, scaling the supply voltage (run-time throttling), and reducing the average current consumption (run-time frequency throttling and clock gating). These techniques are all well known in the art and have enjoyed some success in reducing the average power consumption of the device.
In reality, the average power consumption of the device is only one component of battery life. Further increases in battery life may be realized by increasing the efficiency by which the battery delivers energy to the various processing resources. The need for a battery efficient system is clear in wireless communications supporting 3G services. In these devices, traditional power management schemes directed to reducing average power consumption may not provide acceptable battery life. Accordingly, there is a need in the art for a battery efficient system that may be used alone, or in combination with other power management techniques, to increase battery life.